Consumer convenience is a major concern in using automatic transaction systems, such as vending machines. Many vending machine customers often do not have exact change, and thus the machines typically are capable of making change. However, if the vending machine coin tubes that are used to dispense change are low or empty, then deposit of exact change is often required. In such an instance, a customer may be unable to purchase an item he wanted and, correspondingly, a sale of that item may be lost.
Conventional vending machines typically have coin tubes for dispensing change corresponding to all of the denominations of coins that can be accepted by the coin validator. However, in some cases the lowest value coin denomination that can be accepted by the machine does not have a coin tube associated with it. For example, there are vending machines that accept pennies, nickels, dimes and quarters and do not contain penny coin tubes. A problem arises when nickels used for change in such an apparatus are in short supply or if the nickel coin tube is empty. In such a case, the apparatus can only make change in either limited combinations of nickels and other coins or only in dimes and quarters. Such machines often then require the deposit of exact change only from a customer, which may be displayed electronically for a customer by virtue of an "exact change" LED indicator or scrolling display on the front panel of the vending machine. The drawback of operating in such a manner is that some customers will not be able to purchase an item even though they would prefer to overpay slightly to receive it than to have a nickel or the like in change returned.
Another problem arises when a vending machine is capable of accepting high-value coins, such as dollar coins, that do not have a corresponding coin tube. In some cases, for example, if the amount of change in the coin tubes is low, the vending machine will not accept any non-tubed coin, even if it could be combined with a denomination having a coin tube to equal the price of an item for sale in the machine.
Therefore, there is a need for a coin acceptance method for a vending machine which will enable a customer to overpay slightly in order to receive a product or service. In addition, there is a need for a method for a vending machine which will enable a customer to insert a high-value, non-tubed coin into the vending machine in situations where some coin tubes are low or empty but the vend prices of items in the machine may permit the use of such a coin.